In industry and commerce, there are many types of products which must be packaged in order to protect them from exposure to the elements during shipping and storage. It is common practice, for this purpose, to use a clear plastic sheet that is wrapped around the item to be packaged. This is generally accomplished by extending a sheet of plastic across an opening and conveying the product through the opening transversely to the plane of the sheet. For this reason there is a minimum of tension on the film to allow the product to move against the sheet and extend the sheet as it passes through the opening. Portions of the sheet above and below the product are brought together behind the product and severed to free the product from the plastic sheet. The free ends of the film extending from the product are fused to form a complete package around the product. The ends away from the product are fused to extend a new sheet across the opening for the next product. In a typical operation, two rolls of plastic are used, one above and one below the opening through which the products are conveyed. The ends of each roll are fused together to form a continuous curtain of plastic film across the opening. Since the film is wrapped around the product with a minimum of tension, a preshrinkable plastic film is often used and the wrapped products are subjected to heat treatment for shrinkage in an oven commonly referred to as a shrink tunnel. Equipment for carrying out this operation is complex, expensive, and usually quite large. The heat shrinking operation constitutes an added manufacturing step which requires considerable space and absorbs considerably energy. These and other difficulties experienced with the prior art devices have been obviated in a novel manner by the present invention.
It is, therefore, an outstanding object of the invention to provide a method of and apparatus for wrapping generally cylindrical items with plastic sheet from a single source of supply.
Another object of the invention is the provision of the method of and apparatus for wrapping a generally cylindrical product with plastic sheet under sufficient tension to produce a finished wrapped product without the need of a heat shrinking operation.
A further object of the present invention is the provision of automatic machinery for wrapping a cylindrical product placed within the machinery and to discharge the wrapped product from the machinery after wrapping.
It is another object of the instant invention to provide apparatus which will automatically carry out selected steps of the wrapping method of the present invention, the remaining steps being performed by hand operation.
A still further object of the invention is the provision of apparatus for wrapping generally cylindrical products of different diameters.
It is a further object of the invention to provide apparatus for wrapping products utilizing plastic film which is of a relatively tacky nature which will adhere to the product but which can be separated from engaging machine elements by the use of pressurized air.
It is a further object of the invention to provide apparatus for wrapping generally cylindrical products which are simple in construction, which is inexpensive to manufacture, and which occupies a minimum of floor space during use.
With these and other objects in view, as will be apparent to those skilled in the art, the invention resides in the combination of parts set forth in the specification and covered by the claims appended hereto.